Manhole cover



Nov. 24, 1931. I R. e. REDM7ANQNMI I MANHOLE COVER Filed July 8, 192

A TTORNEYS.

- Patented Nov. 24, 1931 UNITED STATES 303mm G. REDMANN, OF BRISTOL, connnc'rrcu'r, Assreivoa "roman FOUNDRY COMPANY, or mus'ron, connncrrcv'nn conrone'rron MANHOLE covEBQj Application filed m s, 1929. Serial 'n sa,8a., f,

My invention relates to improvements in' manhole covers, of the form involving the use of a casing or boxing that is set in'the ground or roadway and a cover for closing the upper. end thereof, and the objectof my improvement is to produce aboxing and cover combination in which the seat in the boxing is provided in an inwardly projecting flange that is interrupted at intervals by cross-slots for admitting the ends of a locking structure on thecover, whlch ends serve as looking lugs in engagement with the under V Figure 1 is a side elevation of a manhole boxing and cover structure embodying my invention, a wrench being shown in engagement with the cover. 1

' Fig. 2 is a plan view of the same.

Fig. 8 is a sectional view on an enlarged scale on the line 33 of Fig. 2.

Fig. 4 is a bottom view of the cover.

Fig. 5 is a bottom view of the boxing.

Fig. 6 is a fragmentary sectional View through one of the locking joints.

Fig. 7 is another fragmentary view, part in section, showing from the inside a portion of one of the seat supporting ribs or flange structures and one of the'locking lugs.

My improved manhole cover 10 is used in combination with a base member or ring 11 that terminates at the upper 'endin the form of a rim 12 that is set flush with the roadway- The cover 10 fits within said rim 12, with the top face also flush with'the roadway, there being just inside the rim 12 a depressedseat 1-1 for the edge portion 0f the cover 10.

The seat 14 is the up er face of aflan e 18.=

5 Thus, responsive to turning the cover in the I claim as my inventionz present instance, and with a proper proporsessions r'ight fdirection, which is clockwise in"*the' stopped after a'forcefulengagement that serves to effect a positive locking ofthg (f v and to provide a tight seating of :thefedge "Portion 15 ofth'e cover'10 on the seat 14.

' I prefer to subdividethe under face 17 of 1 the seat supporting structure18 by means of .60

in number, and spaced angularly at one" hundred and twenty degree intervals-and a plurality of. cross-slots 19, as shown, three thus provide a-correspondingfnumber of clinedin the'manner described.

under face sections'117 ,eachfof'whichisim The 10 king lug structure that engages the three under face sections I1? comprises a set-of locking 'lugs'20' thatv are supportedifrom the under .face ofthe cover .10 fb'ysupporting I rib structurefl-l orthe like'so as to ,be in spaced relation fromthe cover by a separating space 22 such as toadmit the seat supporting flange 18 and to operatively engage therewith in the manner described. V

The base member and cover described; are made of cast iron. In use they are subjected to severe conditions, involving 1changesin weather and temperature. Also, the parts are of relatively large diameter. The posi.-'

under present forms of construction covers become loose, rock as traffic passes thereover,

tive lock described isextremely desirable, as i resulting in objectionable noises as well as damage, in some instances being actually thrown off from the seats and away from the openmg.

I find that the structure described can be relied upon for satisfactory service, particularly by the'use of releasing means in the form of a relatively large wrench-23 having engaging means for connectingwith the cover spaced apartso-as to engage with depressions 25. in--the cover .10 that are relatively close to the periphery of the cover. Thewrench 23 is a relatively large spannerwrench.

, 10 in the form of dependent pins 24 that are f may be forcibly disengaged.

In manhole cover construction, 'an'annular Q base having a generally cylindrical'wall that is, provided adjacent the upper end With an inwardly projecting flange structure that has a plain upper face that serves as a seat, said flange structure being inte'rrupted'by a plus r ality o'f cr0ss-slotsthat subdividethe flange structure into a corresponding plurality of flange-sections, said slots opening into the inrterior "open space of the base and :;te'r.minat-.v 7, ing outwardly radi'allyin spaced relaitionzto-i the outer edge of the flange structure, leaving intact a seat portion at theend of the- 5 slot thatmerges With the adjacent seat pol? tions on the 'tWo sides to'provide'a continuous uninterruptedseat :fac.e,--said flange=sections 1 being thickened generally below said :seat i n generallyjwedgelike' formflwith. thelbfottom face of each 'flang'e s ection othelical form, a cover fitting over on top of sald seat so as to substantiallyfullycover thesamebytheunder face of the peripheral portion and provided 7 on the under face with a;plura1ityoflugs,' one for; each. of said lslots a'nd adapted to drop through said slotsand to engage when the vcover is turned With'the said helical bottom I V 'faces by vtheir. upperafaces said upper :faces' of theflugsjbe'ing spaced fromsaidunder face ,7 of the .periphieral''portion soas toper'mit of initial 'free turning of the cover "froin po'sn ti'on ofregistrationof the lugs withthe slots I I and .as the turning-is continued to pinch the V fiange section in each case for effecting a positlueholding-tofthe cover. i

ROBERT G; REDMANN.

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